If you're honest about the time you take and the time you do it, she really shouldn't have a basis to complain and if she continues harrassing you, tell the landlord, though if there's is some kind of relatively clean (not pile type) kind of thin padding or something you can put underneath, it could be worth a try. Why not ask a sporting goods place (or t-mill mgfr.) for ideas.

Do you run or walk on the treadmill? My spouse likes to jog on ours upstairs, I can feel it reverberate from the first floor. There is a pad under it but that doesn't seem to make much of a difference.

Early evening for only 1/2 an hour doesn't seem unreasonable. I would try to find out what is specifically bothering the neighbor about your treadmill use. Is it noise or vibration?

Maybe the neighbor just returned from work, is trying to watch a favorite show and is unable to hear it above the noise. Can you move the treadmill to another spot?

Vacuuming can be similarly noisy yet I doubt the neighbor might complain about this.

Perhaps you could talk to your landlord and see if he/she could speak to the neighbor to find out what it is that is bothering him/her.

The landlord might be willing to help mediate a solution that works for both of you.

I walk on the treadmill which is why I didn't think the vibration would be the problem, but I'm not really sure what the problem is. I'm guessing it's the noise of the motor but I don't know for sure. What type of a pad is under your treadmill? Is it something made specifically for a treadmill?

I know the neighbor isn't returning from work in the evening because she never goes out. I guess maybe I'm using the treadmill while she's watching Jeopardy lol. I have no idea. The only other option for moving the treadmill would be into the bedroom. I have it in a corner in the living room now. I guess I really need to ask the landlord what the specific issue is.

I might suggest putting it in the bedroom--few people are in their bedrooms in the early evening, so you'd probably cut down on the problem.

And it would certainly make you look as though you're willing to try to do something.

One thing I've found: people who get used to lots of quiet find themselves really shocked when noise does arrive.

So if she's home all day when you're at work, ANY noise you make is going to seem as though you're extra loud.

Dreamgarden mentioned vacuuming--but I had a situation in which my downstairs neighbor went BALLISTIC when I vacuumed.

We had a toddler, and we were almost never home, and I hadn't vacuumed in literally months. We left for work before 8am (her in tow). We came home about 7pm, immediately ate, and put her directly in to bed. So I had very little time to vacuum (our place is small enough, I couldn't vacuum when she was sleeping. Then, we were away on the weekends a LOT, so I didn't vacuum.

One Friday night we got home at 7:30, and had already eaten. I grabbed my opportunity to vacuum, sand suddenly he was banging on the ceiling (using his oars, since the ceilings are 9.5 feet).

Because it had been SO long since we'd vacuumed, he felt we were too loud.

Then, the lady upstairs from me was very old and ill. And then she died and the place sat empty. After about a year, someone started taking care of the place, vacuuming weekly. It sounded so loud, and it was really intrusive. I realized that was because the upstairs neighbor had seldom (or never) vacuumed, or if she did, she did it midday when we weren't around.

So if you can do something conciliatory, then you maybe can just give her time to get used to it.

There are pads for exercise equipment. i think that would be good if you can afford it.

http://www.soundproofing.org/infopages/vibrationpads.htm

http://www.customrubbercorp.com/l_pads.htm?referrer=adwords&keyword=vibration_pad